A basic investigation is proposed to determine the origin and mechanism of disc degeneration. An original hypothesis, which provides a cogent and consistent explanation of the mechanism of disc degenera-tion and its relationship to low back pain, is advanced as the basis of a logical series of experiments. The spinal elements of Rhesus monkeys will be subjected to predetermined levels and modes of stress in vivo. The temporal, chemical, structural and electrical response of the spinal elements, as a function of stress, will be determined from in vivo measurements as well as histological examination of excised specimens. The results obtained will be used to verify, modify and/or extend the proposed hypothesis.